/**
* Re-write query into primitive queries in the context of specified index
*
* @param \Zend\Search\Lucene\SearchIndex $index
* @throws \Zend\Search\Lucene\Exception\OutOfBoundsException
* @return \Zend\Search\Lucene\Search\Query\AbstractQuery
*/
public function rewrite(Lucene\SearchIndex $index)
{
$this->_matches = array();
if ($this->_field === null) {
// Search through all fields
$fields = $index->getFieldNames(true);
} else {
$fields = array($this->_field);
}
$maxTerms = Lucene\Lucene::getTermsPerQueryLimit();
foreach ($fields as $field) {
$index->resetTermsStream();
if ($this->_lowerTerm !== null) {
$lowerTerm = new Index\Term($this->_lowerTerm->text, $field);
$index->skipTo($lowerTerm);
if (!$this->_inclusive && $index->currentTerm() == $lowerTerm) {
// Skip lower term
$index->nextTerm();
}
} else {
$index->skipTo(new Index\Term('', $field));
}
if ($this->_upperTerm !== null) {
// Walk up to the upper term
$upperTerm = new Index\Term($this->_upperTerm->text, $field);
while ($index->currentTerm() !== null && $index->currentTerm()->field == $field && $index->currentTerm()->text < $upperTerm->text) {
$this->_matches[] = $index->currentTerm();
if ($maxTerms != 0 && count($this->_matches) > $maxTerms) {
throw new OutOfBoundsException('Terms per query limit is reached.');
}
$index->nextTerm();
}
if ($this->_inclusive && $index->currentTerm() == $upperTerm) {
// Include upper term into result
$this->_matches[] = $upperTerm;
}
} else {
// Walk up to the end of field data
while ($index->currentTerm() !== null && $index->currentTerm()->field == $field) {
$this->_matches[] = $index->currentTerm();
if ($maxTerms != 0 && count($this->_matches) > $maxTerms) {
throw new OutOfBoundsException('Terms per query limit is reached.');
}
$index->nextTerm();
}
}
$index->closeTermsStream();
}
if (count($this->_matches) == 0) {
return new EmptyResult();
} else {
if (count($this->_matches) == 1) {
return new Term(reset($this->_matches));
} else {
$rewrittenQuery = new MultiTerm();
foreach ($this->_matches as $matchedTerm) {
$rewrittenQuery->addTerm($matchedTerm);
}
return $rewrittenQuery;
}
}
}
/**
* Re-write query into primitive queries in the context of specified index
*
* @param \Zend\Search\Lucene\SearchIndex $index
* @throws \Zend\Search\Lucene\Exception\RuntimeException
* @throws \Zend\Search\Lucene\Exception\OutOfBoundsException
* @return \Zend\Search\Lucene\Search\Query\AbstractQuery
*/
public function rewrite(Lucene\SearchIndex $index)
{
$this->_matches = array();
if ($this->_pattern->field === null) {
// Search through all fields
$fields = $index->getFieldNames(true);
} else {
$fields = array($this->_pattern->field);
}
$prefix = self::_getPrefix($this->_pattern->text);
$prefixLength = strlen($prefix);
$matchExpression = '/^' . str_replace(array('\\?', '\\*'), array('.', '.*'), preg_quote($this->_pattern->text, '/')) . '$/';
if ($prefixLength < self::$_minPrefixLength) {
throw new RuntimeException('At least ' . self::$_minPrefixLength . ' non-wildcard characters are required at the beginning of pattern.');
}
/** @todo check for PCRE unicode support may be performed through Zend_Environment in some future */
if (@preg_match('/\\pL/u', 'a') == 1) {
// PCRE unicode support is turned on
// add Unicode modifier to the match expression
$matchExpression .= 'u';
}
$maxTerms = Lucene\Lucene::getTermsPerQueryLimit();
foreach ($fields as $field) {
$index->resetTermsStream();
if ($prefix != '') {
$index->skipTo(new Index\Term($prefix, $field));
while ($index->currentTerm() !== null && $index->currentTerm()->field == $field && substr($index->currentTerm()->text, 0, $prefixLength) == $prefix) {
if (preg_match($matchExpression, $index->currentTerm()->text) === 1) {
$this->_matches[] = $index->currentTerm();
if ($maxTerms != 0 && count($this->_matches) > $maxTerms) {
throw new OutOfBoundsException('Terms per query limit is reached.');
}
}
$index->nextTerm();
}
} else {
$index->skipTo(new Index\Term('', $field));
while ($index->currentTerm() !== null && $index->currentTerm()->field == $field) {
if (preg_match($matchExpression, $index->currentTerm()->text) === 1) {
$this->_matches[] = $index->currentTerm();
if ($maxTerms != 0 && count($this->_matches) > $maxTerms) {
throw new OutOfBoundsException('Terms per query limit is reached.');
}
}
$index->nextTerm();
}
}
$index->closeTermsStream();
}
if (count($this->_matches) == 0) {
return new EmptyResult();
} else {
if (count($this->_matches) == 1) {
return new Term(reset($this->_matches));
} else {
$rewrittenQuery = new MultiTerm();
foreach ($this->_matches as $matchedTerm) {
$rewrittenQuery->addTerm($matchedTerm);
}
return $rewrittenQuery;
}
}
}
/**
* Re-write query into primitive queries in the context of specified index
*
* @param \Zend\Search\Lucene\SearchIndex $index
* @throws \Zend\Search\Lucene\Exception\OutOfBoundsException
* @return \Zend\Search\Lucene\Search\Query\AbstractQuery
*/
public function rewrite(Lucene\SearchIndex $index)
{
$this->_matches = array();
$this->_scores = array();
$this->_termKeys = array();
if ($this->_term->field === null) {
// Search through all fields
$fields = $index->getFieldNames(true /* indexed fields list */);
} else {
$fields = array($this->_term->field);
}
$prefix = Index\Term::getPrefix($this->_term->text, $this->_prefixLength);
$prefixByteLength = strlen($prefix);
$prefixUtf8Length = Index\Term::getLength($prefix);
$termLength = Index\Term::getLength($this->_term->text);
$termRest = substr($this->_term->text, $prefixByteLength);
// we calculate length of the rest in bytes since levenshtein() is not UTF-8 compatible
$termRestLength = strlen($termRest);
$scaleFactor = 1/(1 - $this->_minimumSimilarity);
$maxTerms = Lucene\Lucene::getTermsPerQueryLimit();
foreach ($fields as $field) {
$index->resetTermsStream();
if ($prefix != '') {
$index->skipTo(new Index\Term($prefix, $field));
while ($index->currentTerm() !== null &&
$index->currentTerm()->field == $field &&
substr($index->currentTerm()->text, 0, $prefixByteLength) == $prefix) {
// Calculate similarity
$target = substr($index->currentTerm()->text, $prefixByteLength);
$maxDistance = isset($this->_maxDistances[strlen($target)])?
$this->_maxDistances[strlen($target)] :
$this->_calculateMaxDistance($prefixUtf8Length, $termRestLength, strlen($target));
if ($termRestLength == 0) {
// we don't have anything to compare. That means if we just add
// the letters for current term we get the new word
$similarity = (($prefixUtf8Length == 0)? 0 : 1 - strlen($target)/$prefixUtf8Length);
} else if (strlen($target) == 0) {
$similarity = (($prefixUtf8Length == 0)? 0 : 1 - $termRestLength/$prefixUtf8Length);
} else if ($maxDistance < abs($termRestLength - strlen($target))){
//just adding the characters of term to target or vice-versa results in too many edits
//for example "pre" length is 3 and "prefixes" length is 8. We can see that
//given this optimal circumstance, the edit distance cannot be less than 5.
//which is 8-3 or more precisesly abs(3-8).
//if our maximum edit distance is 4, then we can discard this word
//without looking at it.
$similarity = 0;
} else {
$similarity = 1 - levenshtein($termRest, $target)/($prefixUtf8Length + min($termRestLength, strlen($target)));
}
if ($similarity > $this->_minimumSimilarity) {
$this->_matches[] = $index->currentTerm();
$this->_termKeys[] = $index->currentTerm()->key();
$this->_scores[] = ($similarity - $this->_minimumSimilarity)*$scaleFactor;
if ($maxTerms != 0 && count($this->_matches) > $maxTerms) {
throw new OutOfBoundsException('Terms per query limit is reached.');
}
}
$index->nextTerm();
}
} else {
$index->skipTo(new Index\Term('', $field));
while ($index->currentTerm() !== null && $index->currentTerm()->field == $field) {
// Calculate similarity
$target = $index->currentTerm()->text;
$maxDistance = isset($this->_maxDistances[strlen($target)])?
$this->_maxDistances[strlen($target)] :
$this->_calculateMaxDistance(0, $termRestLength, strlen($target));
if ($maxDistance < abs($termRestLength - strlen($target))){
//just adding the characters of term to target or vice-versa results in too many edits
//for example "pre" length is 3 and "prefixes" length is 8. We can see that
//given this optimal circumstance, the edit distance cannot be less than 5.
//which is 8-3 or more precisesly abs(3-8).
//if our maximum edit distance is 4, then we can discard this word
//without looking at it.
$similarity = 0;
} else {
$similarity = 1 - levenshtein($termRest, $target)/min($termRestLength, strlen($target));
}
if ($similarity > $this->_minimumSimilarity) {
$this->_matches[] = $index->currentTerm();
$this->_termKeys[] = $index->currentTerm()->key();
$this->_scores[] = ($similarity - $this->_minimumSimilarity)*$scaleFactor;
if ($maxTerms != 0 && count($this->_matches) > $maxTerms) {
throw new OutOfBoundsException('Terms per query limit is reached.');
}
}
$index->nextTerm();
}
}
$index->closeTermsStream();
}
if (count($this->_matches) == 0) {
return new EmptyResult();
} else if (count($this->_matches) == 1) {
return new Term(reset($this->_matches));
} else {
$rewrittenQuery = new Boolean();
array_multisort($this->_scores, SORT_DESC, SORT_NUMERIC,
$this->_termKeys, SORT_ASC, SORT_STRING,
$this->_matches);
$termCount = 0;
foreach ($this->_matches as $id => $matchedTerm) {
$subquery = new Term($matchedTerm);
$subquery->setBoost($this->_scores[$id]);
$rewrittenQuery->addSubquery($subquery);
$termCount++;
if ($termCount >= self::MAX_CLAUSE_COUNT) {
break;
}
}
return $rewrittenQuery;
}
}
